Plug-in type flat fuse



Dec. 10, 1968 BERNUTZ ET AL PLUG-IN TYPE FLAT FUSE 5 Sheets-Sheet 1 Filed April 19, 1966 Fig. 3 (0/ 3 z 9 a VII/I41? I ll? 4 2 a 3 Fig.4

INVENTORS JOHA mves BEAM/(I72 sum/2 Sci/L664 ,7 BY Z 7 4% ATTORNEY Dec. 10, 1968 Q J BERNUTZ ETAL 3,416,114

PLUG-IN TYPE FLAT FUSE Filed April 19, 1966 3 Sheets-Sheet 2 INVENTORS JOHANNS 86R ivy r2. ELMAR scwz. o c L ATTORNEY Dec. 10, 1968 J. BERNUTZ ET A. 3,416,114

PLUG-IN TYPE FLAT FUSE Filed April 19, 1966 3 Sheets-Sheet 5 INVENTORS JOHANNES BERNUT' Z eLMA/z sc/M 6G1.

BY 41% r,

United States Patent ABSTRACT OF THE DISCLOSURE A multi-valued plug-in fuse in which parallel conductors are provided on a plug body of insulating material between which a plurality of fusible leads of different cross-sections are connected. A spark gap is arranged at the ends of the parallel conductors in parallel with the fuse leads.

The invention relates to fuses and more particularly to a flat fuse, capable of being plugged into spring strips.

There are plug-in type flat fuses known to be used in receptacles in order to avoid an excessive load on the main fuse. They consist of a flat insulating body, the ends of which are encompassed by contact pieces and connected with each other by an easily melted wire. These fuses are clamped between two contact springs, arranged in the receptacle. These flat fuses are primarily used for large current service but do not meet the requirements of small current service. They cannot be plugged singleended, cannot be resoldered for another use, cannot be provided with additional contacts and are removable, but on the other hand are relatively expensive.

It is the object of the invention to avoid these advantages. This is achieved, according to the invention, in that conductor leads are provided on the plug body of insulating material between which straps with a defined fusing value and corresponding cross-section are inserted.

According to an embodiment of the invention, fuse straps and conductor leads are applied on the plug body in the form of a printed circuit.

According to a further embodiment of the invention, the flat fuse is made as a standard fuse with fusing strips of different cnoss-section.

In another embodiment of the invention, the fusing strip consists of wire, either welded on or soldered on.

In still another embodiment of the invention, the mechanically biassed fuse wire keeps the study of a contact spring in the open condition and when the wire blows the spring contact is closed and activates a warning device. In a variation of this embodiment a reed contact is kept in open condition through a magnet.

According to a further embodiment of the invention, between two conductive leads several fuse strips are arranged for replugging if the first fuse strip blows.

There are various advantages obtained by the construction according to the invention. The flat fuse can be plugged single-ended, i.e. it can be used in a plug-in system with known spring strips. The flat fuse is moreover manufactured in the kind of printed circuit or provided with fuse wires and straps as conductive leads for higher currents. Furthermore it can be equipped, if so required, with open or closed additional contacts for signalling the operating condition. It is manufactured in the shape of a standard fuse with several fuse strips. The plugin body is'made removable and can be provided with or without an engaging device. Another advantage is the arrangement of the fuse strip between conductive leads of contact combinations.

' 3,416,114 Patented Dec. 10, 1968 The invention is described with the aid of drawings, wherein:

FIGS. 1a and 1b show a simple plug-type fiat fuse seen in two elevations,

FIGS. 10 and 1d show the contact springs which engage the flat fuse,

FIG. 2a shows another construction of the flat fuse as a standard fuse,

FIG. 2b shows the construction of a conductive lead to an air-gap.

FIGS. 3a and 3b show a flat fuse with wire as a fusing strip in two elevations,

FIG. 4 shows a spring strip with different flat fuses and a cable miniature plug,

FIGS. 5a, 5b and 50 show the construction of the fiat fuse as resolderable fuse in three elevations,

FIGS. 6a and 6b show the construction as a resolderable fuse with a reed contact in two elevations,

FIG. 7 shows an unremovable fiat fuse in a separating or disconnecting piece with engaging device in a perspective view, and

FIG. 8 shows a construction with several fusing routes.

FIG. 1 shows a plug-type fiat fuse in which the conductive leads 1 of the copper foil are mutually connected as fuse strips 1'.

The conductive leads in the kind of the printed circuit are applied to the plug-in body 2, provided at its top end with gripping grooves 3, for example. On the plug-in body 2, the value of the fuse 4 is applied, e.g. by stamping. 5 indicates the contact springs of the spring strip 6 (FIG. 4) with which the flat fuse engages when plugging. If required the fuse strip 1 is marked on its surface with a substance which changes the colour at an excessive load or if the fuse blows.

FIG. 2a shows a type of the fiat fuse as standard fuse. Between the leads 1, fuse strips 1' of different crosssection are arranged; the not required fuse strips are eliminated by perforations.

FIG. 2b shows a conductive [lead in which a coarse spark gap 7 is arranged in parallel to the fuse strip 1. For higher amperages the conductive leads are made as strips or ribbons 8, as shown in FIGS. 3a and 3b. This figure shows, moreover, another type whereby the fuse strip is provided in the shape of a wire 9. Said wire 9 is led over a hole 10, the wires cross-section being in compliance with the fusing value. The wire 9 is welded to one conductive lead and soldered to the other one.

FIG. 4 shows a spring strip 6 with various components. Besides four flat fuses with different fuse values 4, a cable miniature plug 11 is plugged into said spring strip. The disconnecting or separating pieces 12 can be seen between the plugged-in elements which also serve to limit shift, engagement and non-removability.

If the fuse wire 9 is mechanically biased, as may be gathered from FIGS. 5 and 6, plug-in type flat resoliderable fuses are obtained. The blowing of these fuses can be indicated either by optical or acoustical signals (not shown).

Switching-in is made by the contact spring 13, the stud 14 of which is normally placed on the fuse wire 9, thus preventing the contact between the leads 30 and 31 until the fuse wire 9 blows. For particular cases, as shown in FIG. 6, a reed contact switch 20 is arranged in the flat fuse, instead of the contact spring 13, so that when the fuse wire 9 melts, a magnet 15 is urged by the spring 16 into a position over the contacts of the reed contact switch 20 so that these contacts close and complete the circuit.

To protect the reed contact switch 20, this embodiment is provided with caps 17.

The plug-in flat fuse cap can also be made in the multistep type, which is particularly economical. This type 3 4 plug can be constructed in a way known to the art for conductive leads, said normal conductive leads being two (FIG. 7) or more than two (FIG. 8), engaging spaced apart to provideaspark gap. positions. The separating piece 12 in FIG. 7 shows to this end cams 18 and the fiat fuse shows a stud 19 on the References cued 5 UNITED STATES PATENTS FIG. 8 demonstrates that when a fuse strip blows the 1,981,735 11/1934 Lipsey 200-125 fiat fuse is put deeper by another step until it engages 2 374 248 2/1959 T d f 1 200-125 next time. Then the next following fuse strip 1" or 1" 2 934, 27 4 19 Bristol et 1 200-129 respectively becomes effective. The contact springs are 2,9 1 059 19 0 i et 1 200-129 shown in rel n to the plugstrips 673,386 5/1901 Courtier 200-12s X The fuse strip 1' can be made in the same method as 70 0 2 3 1902 Hunt 1 goo-.125 the conductive leads 1, but it can also be appli d af r- 1,130,435 3/1915 Davis 335-142 wards by another method, e.g. thin-film technique, evap- 1, 72,2 1 5 1928 hn zoo-415.5 oration or the like. 2,960,584 11/ 1960 Mobarry 335-142 We c1a1m: 3,183,327 5/1965 Kozacka 200-121 1. Aplug-m liat fuse comprising: 3,190,987 6/1965 Fister 200-117 X a f at dlel t member; 3,271,708 9/ 1966 McCormick 335 205 two printed circuit conductive leads attached verti lly 1,848,152 3/1932 Bieger 200-118 X in parallel on the face of said dielectric member; 57 405 11 1951 McAlistelgo -135 X a. plurality of fuse leads attached horizontally on the ,7 0,5 7 10 1 55 Detch 200-435 face of said dielectric member and connecting said 49 2 9 3 1 1 Maxstadt 2()Q 135 X conductive printed circuit leads, each of said fuse leads have a different cross-sectional area, some of BERNARD A, GILHEANY, P i a E i said fuse leads having perforations thereon, so that said perforated fuse leads are rendered inoperative; GILSONAsslstamExammer' said conductive leads are extended beyond said fuse Us cl XR leads; and further comprising conductive leads normal to said 337-273, 255 

